Telephone-exchange system.



i C.L.G00DHUM. TELEPHONE EXCHANGE SYSTEM. APPLICATION FILED MAY 10| 1915.

fQQfhmmm De@ 26, 3916.

www A 'fwy is giveninstructions as to merrain sustains rarnnfr CHARLES L. GOODRUM, OF NEW YORK, N. Y., ASSIGNOB; BY IVESNE ASSIGNMENTS, T0

WESTERN ELECTRIC COMPANY, INCORPORATED, A CORORATON OE NEYV YORK.

TELEPHONE-EXCHANGE SYSTEM.

Specification of Letters Patent.

Patented Dec. 2t?, 1916.

Application filed May 10, 1915. Serial No. 27,053.

a full, clear, concise, and exact description.

rThis invention relates to telephone ex-4 change systems and more particularly to automatic ringing systems tor party lines connected with an automatic telephone exchange.

The object of this invention is toprovide a system whereby upon the establishment of a connection between two parties connected to the same line/Runder the control of a simple switching device controlled preferably by the subscribers switchhook, ring ing currents are applied to said line for signaling both parties.

The drawings represent schematically a telephone system embodying this invention, only as much being shown of the circuits and apparatus as is necessary for the clear understanding of this invention.

There are four parties, connected in multiple to a line 1, 2. Upon the initiation of a call and thesending out of impulses at either station, line 1, Q is extended by means of automatic switches (not shown) to a connector switch 6 in the well kno-wn manner. lEach ot thecparties A-D how many impulses he is tosend out in order to establish a connection with a party connected to his line.

As niell known, in a four party-line systcm ringing current ent frequencies are provided for the signaling of the parties. Supposing for instance that there are current sources of 1G, 33,50 and 6d cycles for signaling parties A, B, C and ll respectively, it will be seen that combir ations (1G-33, .1G-50, 165-66, 323-50, S33-6G, E50-66) of these current sources, will make possible the simultaneous signaling ot any two parties. The ringing current sources of 1G and 33 cycles are adapted to be connected through the first set ot terminals or a selector switch (i, 16 and 50 cycles through the second set of terminals, lf3-(5G through the third, etc. I

It party A desires to obtain connection with party B he sends out impulsesfor caus- A, B, C and D sources ot four differ-- their third position.

ing the extension of line 1, Q to the wipers 3, 4, 5 of selector switch (i, and then by means-of an additional impulse sets wipers 3, 1 and 5 of the-selector switch 6 on terminals 7, 8 and 9 respectively. A circuit is closed from grounded battery 11 through both windings of relay 12-and wipers 13, 1l of a side switch associated with selector l, and then through the calling subscribers loop. Relay 12 becomes'energized and by attracting its armature causes the energization ot slow acting relay 15. The calling party thereupon restores his receiver to the switchhook causing thereby the de'e'nergization of relay 1:2. A circuit is now closed from ground through the armature and back contact of relay 12, armature and front con tact ot slow acting relay 15, and the winding of escapement magnet 1G to grounded battery. Under the control of magnet 16, wipers 13, 1,4 and 17 of the side switch are stepped into the second position. Shortly after the energization of magnet 16, relay 15 becomes denergized. A circuit is now closed from ground through wiper 13, the

subscribers loop, wiper 14e, the winding of ringing relay Q0 andA interruptersQl andv 22 to the two sources of ringing current 23 and Qi, one of which is of 16 cycles for ringing party A and the other one of 33 cycles for ringing party B. Under the control of interrupters 2l and 2Q the two kinds ot ringing` currents arealternatively applied to line 1,2'. In this position otl the side switch relay Q5 cannot become energized, its winding being` short-circuited' through the armature and back contact of ringing relayQQ.l As soon'as'tlie calling and called subscribers remove their receivers from the switchhook. relay' 20 becomes energized, removes Vthe shunt from'the winding of relay 25 and of relay 25 a circuitis closed from ground through 'wiper 17 armature and front contact of relay 25, and the winding oit. escape ment magnet 16 to grounded battery. net 1G moves the side switch wipers into 1n this position of the side switch, relay 25 and, thereby, magnet 16 become -denergized and the ringing circuit is opened. A circuit is now closed through 11e winding/of relay 25 and resistance Q6 to 10o grounded., batter-yf Upon the energization Mag- ' the suhscrihers looimwi'pers 13, Ei over reley l2 and his reloy again becomes energized, energizing in turn the slow acting reiey l5.

n the third position or. he sioe switch,

v subscribersiil und B may converse, talking current being supplie i io their siiions from battery il through resistnnces 30 und 31.

liter the Conversation, rs finished and porties and l have restored heir receivers,.

relay .73 again hecoines decnergized and :i circui is closed through the armature and ront'contucit of relay for eseupemen; nuignet 16 which moves the side switch wipers into their fourth position. A circuit is now closed from ground through wiper 17, conductor 32, oil-normal ffnufuot 33 of switch .(1 and 'winding of release magnet 34 to @rounded batery. Release magnet 34- causes resorzition of selector switch 6 and, ille side switch associatedtherewith, the circui' of this magnet heinf open at 33 us soon as switch (l reaches its normal position. The ground through wiper 17 is upplied also to the Ireiense magnets of the switches which ure used for eritending ehe connection to se.

lector r'irh (E, und Suid switches are restored ihereupon to noi-nml in the well known manner.

v is'hilethe invenion has been described :is 'applied to four-party hue system, it will Leones@ .sitions n'ieans for exgending; Suid line io 'Suid switching device. signaling current sources of different frequencies, u, switchhook for euch stadion, means operative upon `the first zietuaiion of said swi'chhook 'for i'noving seid device ino ite first position.whereby Suid current sources ere connected xiih said line, ineens operative upon n second ucuuion of Seid su'iohhook 'for morini; said (le vice ino its second position AFor oisconnecing Suid currenty sources, und n. reieusing' ineens for said device uruuted in che third position o Suid device. following u third actuation of Suid s\\1i hook.

3. In u party line telephone syseun o line5 n' plurnliy of stations connechfd herefne step-hY-sep switching device huvingthree operuting posiions, signuling currentv sources of di'erent frequencies. n releusing mennel for Suid switching' device. nicuns conirolinhie at said Stations for siiepping Suid device into its various positions whereby the current sources :1re associated with the iine in the irst and dissnssocined 'from the line in the second, :incl 'the releasing ineens operated in the third position of Said device, resper'zively.

n Wifness whereof hereunto subscribe my naine this Sth (luy of May, A. i915.

CHARLES L. GOORUM. 

